1. Field of the Invention
The present invention relates, generally, to molded trim panels for automotive vehicle interiors. More specifically, the present invention relates to a vehicle interior trim panel assembly having an integrated soft-touch armrest and method of manufacturing same.
2. Description of the Related Art
Interior trim automobile components commonly have cushioned, “soft-touch” aesthetic features. In particular, automotive interior panels often have designated cushioned areas in the armrest or center console. These soft-touch areas may be manufactured separate from the interior trim panel, per se, and later assembled thereto or a soft-touch area may be integrated within an interior trim panel during its manufacture. In either event, a soft-touch aesthetic feature may be imparted by a flexible-foam or elastomeric pad of varying thickness surrounded by a coverstock material to provide available cushioned support to the occupants of a vehicle.
Generally, any number of materials may be used as coverstock such as cloth, a polymer skin or leather. Specifically, polymer coverstocks may include polyvinyl, polyvinyl chloride (PVC), thermoplastic olefin (TPO), or thermoplastic urethane (TPU). In vehicle interior trim applications, coverstocks include what is known as a “class-A side”.
The class-A side is the “skin” or finished surface of the polymer coverstock and typically includes a pattern or texture, often simulating the grain of leather. The other side is the “rough” or bond surface of the coverstock that is usually attached to a rigid substrate. The rigid substrate serves as support for the interior trim panel. Generally, the other side of a polymer coverstock includes a thin layer of foam, typically made of polyurethane. Additionally, scrim or some type of a reinforcing agent, such as woven thread, may be applied to the exposed back of the polyurethane foam for structural support. The coverstock is then bonded to the rigid substrate and later assembled to a vehicle as an interior trim panel.
However, there are occasions where an additional amount of foam padding is preferred in certain designated areas, namely door panel armrests, center consoles, head rests and dashboards. As previously noted, door panel armrests and center consoles may be manufactured apart from the manufacture of their respective panels and later assembled. However, issues relative to proper fitting and maintaining a uniform color and texture between the coverstock on the soft-touch area and the rest of the trim panel assembly have been known to arise. Additionally, automotive manufactures generally prefer to reduce costs by reducing the steps in any given manufacture and/or assembly process. As a result, it is preferred to integrate a soft-touch area such as an armrest during manufacture of the entire interior trim panel, where possible.
Several different manufacturing processes are known to manufacture an interior trim panel having an integrated soft-touch aesthetic feature such as an armrest. By way of example, processes involving low pressure molding, structural reaction injection molding, and vacuum forming have all been employed to create an interior panel having an integrated soft-touch aesthetic feature such as an arm rest.
Low Pressure Molding (“LPM”) is a method of injection molding where a thermoplastic material is injected into a mold cavity having a coverstock covering the class A side of the mold cavity. The thermoplastic material flows throughout the mold to conform to the shape of the mold and bond to the coverstock. The bonded materials are then removed from the mold, ready for any secondary finishing operations.
Structural Reaction Injection Molding (“SRIM”) involves forming molded articles between two mold halves. An interior panel incorporating a cushioned armrest made by structural reaction injection molding includes a foam pad sandwiched between a coverstock and a rigid panel substrate. The foam is compressed due to the pressure of molding, e.g., up to about 50 psi, then expands outwardly against the cover as the pressure is released.
Vacuum forming is a process where the thermoplastic coverstock heated, then stretched onto a rigid substrate that has been covered with adhesive using a vacuum. The coverstock and rigid substrate then cure to the shape of the mold.
U.S. Pat. No. 6,183,038 issued on 6 Feb. 2001 to Hansen et al.; U.S. Pat. No. 5,611,977 issued on 18 Mar. 1997 to Takei; U.S. Pat. No. 5,073,318 issued on 17 Dec. 1991 to Rohrlach et al., and; U.S. Pat. No. 4,455,340 issued on 19 Jun. 1984 to Okina, further describe the afore-mentioned methods and variants thereof.
While vehicle interior trim panels having an integrated soft-touch area of the type known in the related art alleviate some of the problems associated with manufacturing this device, there remains a need to reduce costs by reducing the number of steps required to manufacture a vehicle interior trim panel incorporating a soft-touch area. In addition, there remains a need for a vehicle interior trim panel having an integrated soft-touch area. Finally, there remains a need in the art for a vehicle interior trim panel that provides a quality, desirable, class-A surface that is aesthetically pleasing.